<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>basic_deadline_timer::async_wait</title>
    <link rel="stylesheet" href="../../../boostbook.css" type="text/css">
    <meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
    <link rel="home" href="../../../index.html" title="Asio">
    <link rel="up" href="../basic_deadline_timer.html" title="basic_deadline_timer">
    <link rel="prev" href="../basic_deadline_timer.html" title="basic_deadline_timer">
    <link rel="next" href="basic_deadline_timer.html" title="basic_deadline_timer::basic_deadline_timer">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%">
    <tr>
        <td valign="top"><img alt="asio C++ library" width="250" height="60" src="../../../asio.png"></td>
    </tr>
</table>
<hr>
<div class="spirit-nav">
    <a accesskey="p" href="../basic_deadline_timer.html"><img src="../../../prev.png" alt="Prev"></a><a accesskey="u"
                                                                                                        href="../basic_deadline_timer.html"><img
        src="../../../up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../home.png"
                                                                                            alt="Home"></a><a
        accesskey="n" href="basic_deadline_timer.html"><img src="../../../next.png" alt="Next"></a>
</div>
<div class="section">
    <div class="titlepage">
        <div>
            <div><h4 class="title">
                <a name="asio.reference.basic_deadline_timer.async_wait"></a><a class="link" href="async_wait.html"
                                                                                title="basic_deadline_timer::async_wait">basic_deadline_timer::async_wait</a>
            </h4></div>
        </div>
    </div>
    <p>
        <a class="indexterm" name="asio.indexterm.basic_deadline_timer.async_wait"></a>
        Start
        an asynchronous wait on the timer.
    </p>
    <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
    <span class="keyword">typename</span> <a class="link" href="../WaitToken.html" title="Wait token requirements">WaitToken</a> <span
                class="special">=</span> <a class="link"
                                            href="../asynchronous_operations.html#asio.reference.asynchronous_operations.default_completion_tokens"><span
                class="emphasis"><em>DEFAULT</em></span></a><span class="special">&gt;</span>
<a class="link"
   href="../asynchronous_operations.html#asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type"><span
        class="emphasis"><em>DEDUCED</em></span></a> <span class="identifier">async_wait</span><span
                class="special">(</span>
    <span class="identifier">WaitToken</span> <span class="special">&amp;&amp;</span> <span
                class="identifier">token</span> <span class="special">=</span> <a class="link"
                                                                                  href="../asynchronous_operations.html#asio.reference.asynchronous_operations.default_completion_tokens"><span
                class="emphasis"><em>DEFAULT</em></span></a><span class="special">);</span>
</pre>
    <p>
        This function may be used to initiate an asynchronous wait against the
        timer. It is an initiating function for an <a class="link" href="../../overview/model/async_ops.html"
                                                      title="Asynchronous Operations">asynchronous
        operation</a>, and always returns immediately.
    </p>
    <p>
        For each call to <code class="computeroutput"><span class="identifier">async_wait</span><span
            class="special">()</span></code>, the completion handler will be called
        exactly once. The completion handler will be called when:
    </p>
    <div class="itemizedlist">
        <ul class="itemizedlist" type="disc">
            <li class="listitem">
                The timer has expired.
            </li>
            <li class="listitem">
                The timer was cancelled, in which case the handler is passed the error
                code <code class="computeroutput"><span class="identifier">asio</span><span
                    class="special">::</span><span class="identifier">error</span><span class="special">::</span><span
                    class="identifier">operation_aborted</span></code>.
            </li>
        </ul>
    </div>
    <h6>
        <a name="asio.reference.basic_deadline_timer.async_wait.h0"></a>
        <span><a name="asio.reference.basic_deadline_timer.async_wait.parameters"></a></span><a class="link"
                                                                                                href="async_wait.html#asio.reference.basic_deadline_timer.async_wait.parameters">Parameters</a>
    </h6>
    <div class="variablelist">
        <p class="title"><b></b></p>
        <dl>
            <dt><span class="term">token</span></dt>
            <dd>
                <p>
                    The <a class="link" href="../../overview/model/completion_tokens.html" title="Completion Tokens">completion
                    token</a> that will be used to produce a completion handler, which
                    will be called when the timer expires. Potential completion tokens
                    include <a class="link" href="../use_future.html" title="use_future"><code
                        class="computeroutput"><span class="identifier">use_future</span></code></a>,
                    <a class="link" href="../use_awaitable.html" title="use_awaitable"><code
                            class="computeroutput"><span class="identifier">use_awaitable</span></code></a>,
                    <a class="link" href="../yield_context.html" title="yield_context"><code
                            class="computeroutput"><span class="identifier">yield_context</span></code></a>,
                    or a function object with the correct completion signature. The function
                    signature of the completion handler must be:
                </p>
                <pre class="programlisting"><span class="keyword">void</span> <span
                        class="identifier">handler</span><span class="special">(</span>
  <span class="keyword">const</span> <span class="identifier">asio</span><span class="special">::</span><span
                            class="identifier">error_code</span><span class="special">&amp;</span> <span
                            class="identifier">error</span> <span class="comment">// Result of operation.</span>
<span class="special">);</span>
</pre>
                <p>
                    Regardless of whether the asynchronous operation completes immediately
                    or not, the completion handler will not be invoked from within this
                    function. On immediate completion, invocation of the handler will
                    be performed in a manner equivalent to using <a class="link" href="../post.html" title="post"><code
                        class="computeroutput"><span class="identifier">post</span></code></a>.
                </p>
            </dd>
        </dl>
    </div>
    <h6>
        <a name="asio.reference.basic_deadline_timer.async_wait.h1"></a>
        <span><a name="asio.reference.basic_deadline_timer.async_wait.completion_signature"></a></span><a class="link"
                                                                                                          href="async_wait.html#asio.reference.basic_deadline_timer.async_wait.completion_signature">Completion
        Signature</a>
    </h6>
    <pre class="programlisting"><span class="keyword">void</span><span class="special">(</span><span class="identifier">asio</span><span
            class="special">::</span><span class="identifier">error_code</span><span class="special">)</span>
</pre>
    <h6>
        <a name="asio.reference.basic_deadline_timer.async_wait.h2"></a>
        <span><a name="asio.reference.basic_deadline_timer.async_wait.per_operation_cancellation"></a></span><a
            class="link"
            href="async_wait.html#asio.reference.basic_deadline_timer.async_wait.per_operation_cancellation">Per-Operation
        Cancellation</a>
    </h6>
    <p>
        This asynchronous operation supports cancellation for the following <a class="link"
                                                                               href="../cancellation_type.html"
                                                                               title="cancellation_type"><code
            class="computeroutput"><span class="identifier">cancellation_type</span></code></a>
        values:
    </p>
    <div class="itemizedlist">
        <ul class="itemizedlist" type="disc">
            <li class="listitem">
                <code class="computeroutput"><span class="identifier">cancellation_type</span><span
                        class="special">::</span><span class="identifier">terminal</span></code>
            </li>
            <li class="listitem">
                <code class="computeroutput"><span class="identifier">cancellation_type</span><span
                        class="special">::</span><span class="identifier">partial</span></code>
            </li>
            <li class="listitem">
                <code class="computeroutput"><span class="identifier">cancellation_type</span><span
                        class="special">::</span><span class="identifier">total</span></code>
            </li>
        </ul>
    </div>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%">
    <tr>
        <td align="left"></td>
        <td align="right">
            <div class="copyright-footer">Copyright © 2003-2022 Christopher M. Kohlhoff<p>
                Distributed under the Boost Software License, Version 1.0. (See accompanying
                file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
            </p>
            </div>
        </td>
    </tr>
</table>
<hr>
<div class="spirit-nav">
    <a accesskey="p" href="../basic_deadline_timer.html"><img src="../../../prev.png" alt="Prev"></a><a accesskey="u"
                                                                                                        href="../basic_deadline_timer.html"><img
        src="../../../up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../home.png"
                                                                                            alt="Home"></a><a
        accesskey="n" href="basic_deadline_timer.html"><img src="../../../next.png" alt="Next"></a>
</div>
</body>
</html>
